Evaluated in a 3-year project were the effects of three different classroom settings (a graded open classroom with a resource teacher, a multigrade open classroom emphasizing individualized instruction, and two self-contained special education classrooms) on achievement, self-concept, and classroom behavior of 30-38 educable mentally retarded children 8- to 13-years-old. Analysis of pre- and posttest measures of self-concept, achievement, attitudes, and classroom behavior did not demonstrate that one setting was clearly superior to another in producing meaningful gains in academics, self-concept, or attitudes toward schooling. Open classrooms promoted more peer interaction while the self-contained setting elicited more attending and teacher directed behavior. Teachers perceived Ss in open settings less favorably than Ss in self-contained classrooms. Associated with academic success were the learning characteristics of attention and independence. Task-oriented peer interaction, sociodrama, role playing techniques, and the use of media programs to assist instruction in alternative settings were found to be positive program components. Seven appendixes provide such information as a listing of topics covered during the sociodrama sessions and a list of media productions. (CL)